Estrous induction and conception rate with artificial insemination in Osmanabadi goats

Introduction

Artificial oestrus synchronization regulation is useful techniques used effectively to improve reproductive efficiency and intervals of kidding. Breeding timing may be predetermined by using various assisted reproductive technologies. Oestrus synchronization would be more useful in seasonally breeding goats as it confirms a very good rate of conception which ultimately establishes a normal pregnancy. Goat is a spontaneous ovulator with a period of 20-21 days in the estrus cycle, more or less similar to cow. This oestrus period is 1 to 2 days, and ovulation occurs 24-36 hours after estrus onset. Therefore, induction and estrus synchronization is an important management method that has been used as an aid to Artificial Insemination (A.I) and to reduce the seasonal effects in dairy goat reproduction. During the estrus synchronization system, the use of A.I is encouraged by applying different estrous synchronization protocol. Essentially, there are two methods for the synchronization of estrus in goats: artificial prolongation of diestrus using exogenous progesterone or progestagen, or shortening this process by using luteolytic agents (Bretzlaff and Madrid, 1989) [2] . Synchronization can be done by using ProstaglandinF2alpha, GnRH or intravaginal progesterone sponges.

Controlling goat reproduction provides three key advantages:

(1) selecting a kidding cycle at a particular season of the year (determined by the availability of forage or selling of products), (2) coordination of kidding over a limited period of time (labor control, reduction of kid mortality, homogeneous feeding of mothers and kids) and (3) gene management. Therefore, this research trial is taken up with the following objective for estrus induction and conception rate with GnRH, PGF2α and GnRH protocol by artificial insemination in Osmanabadi goats.

Materials and Methods

The research work was carried on "Estrus induction and conception rate with artificial insemination in Osmanabadi goats" at Teaching Veterinary Clinical Complex, Instructional Livestock Farm Complex of College of Veterinary and Animal Sciences Parbhani, Private professional goat farms of Parbhani district and in University goat unit of Vasantrao Marathwada Agriculture University Parbhani.

Selection of experimental animals

A total of 48 healthy Osmanabadi does were selected as experimental animals for the research work. All the does were selected without any genital abnormality irrespective of the ovarian activity and were screened for ruling out early pregnancy by B-mode ultrasonography either by transabdominally or trans-rectally.

Schedule of treatment protocol

After selection of experimental animals, total 48 Osmanabadi goats were randomly divided into two groups each consists of 24 does and were maintained under isolation from the remaining goats. The does from these two groups were treated with control breeding protocol with one control group. A total of 48 Osmanabadi does will be divided into 2 groups, each group consisting of 24 does. Group-I comprises of 24 does as control group which will be untreated and in Group-II with ovsynch protocol by administering GnRH@4µg I.M on day 0, PGF2alpha @125µg I.M on day 7th and 2 nd GnRH@4µg i.m on day 9 th .

Reproductive Observations

The estrus response was determined by the number of does in estrus divided by the number of does treated and multiplied by 100 and it is expressed in per cent. Time to onset of estrous was calculated from the time of the end of treatment to first appearance of estrous signs. The time for exhibition of estrous in terms of hours. Time of first acceptance of mating to the last acceptance of mating was recorded as duration of estrus and it is expressed in hours. The conception rate was determined by the number of does pregnant divided by the number of goats inseminated multiplied by hundred and it is expressed in per cent after Artificial insemination was carried. A real time B-mode portable ultrasonography machine (SSD-500 Aloka Co. Ltd., Japan) was used for pregnancy diagnosis. All the observations of the experiment were recorded systematically as per protocol. The data was properly tabulated and was statistically analyzed by using one-way Anova followed by Duncan test as post hoc test.

Results and Discussion

Out of 24 does 6 does were exhibited the estrous symptoms and the estrous response was 25% in group I (control group). In group II out of 24 does 20 does were exhibited the estrous symptoms and the estrous response was 83.33%. (Table 1). Similar findings were reported by Thombre (2016) [11] , Takle, (2018) [10] and Nur et al., (2013) [6] with 83.33%, 83.33% and 84% of estrous response respectively. Similar results were also reported by Pujar et al., (2016) [7] with 84.61% of estrous response in Osmanabadi goats. In contrary with the present findings Holtz et al. (2008) [5] , obtained higher estrous response as 96%.Contrary results were are also reported by Sneha et al., (2015) [9] , Gupta et al., (2019) [3] and Hashem et al., (2015) [4] with the lower estrous response as 75%, 51.72% and 42.85% respectively. [9] and Takle, (2018) [10] who quoted mean (± S.E.) time for the onset of estrous as 49.92±1.94hrs and 51.67±1.58hrs, respectively.

In contrary with the present findings Hashem et al., (2015) [4] and Nur et al., (2013) [6] observed lower mean (± S.E.) time for the onset of estrous as 34±2.1 hrs. and 30.9 hrs., respectively. It is evident from table 2 that mean (± S.E.) of the time taken for onset of estrous was significantly different in all group (p<0.01). It is clear that, the time required for the onset of estrous was lowest in group II does as with the control group. Significant differences in the time taken for the onset of estrous between the groups was observed could be due to selection of experimental goats with the irrespective of ovarian activity and age. These differences could also be due to difference in the time of hormonal treatment and different estrous induction protocol. Mean (± S.E.) of duration of estrous was calculated between the first and last acceptance of male within the same estrous period in hours. In group II mean (± S.E.) of the duration of estrous was 35.10±0.67 hrs. While the mean duration of estrous in control group was 19.83±1.21. The mean duration of estrous in both the groups varied significantly (p<0.01). Similar observation was also reported by Thombre, (2016) [11] who observed the mean (± S.E.) of the duration of estrous as 39.6±0.56hrs. In contrast with the present findings lesser mean (± S.E.) of the duration of estrous was observed by Riaz et al., (2011) [1] and Nur et al., (2013) [6] as 24±3.7 hr. and 29.4 hr., respectively. The present findings are also not in agreement with the Takle, (2018) [10] who observed higher mean (± S.E.) of the duration of estrous as 43.42±0.57hrs. It is evident from table 3 that mean (± S.E.) of the duration of estrous was significantly varied in all group (p<0.01). The results variations may be due to individual differences within same species, change in the treatment protocol, duration in the administration of hormone protocol timings in the above-mentioned experiment. The differences in the observation of duration of estrous reported by earlier author may be because of breed variation, seasonal variation, age differences. From the present findings, it is clear that, duration of estrous was observed highest in group II as compared to control group of goats during the research work. Pregnancy conformation was done by using a real time B mode ultrasonography machine on day 35 th after artificial insemination to obtain the conception rate. The conception rate was determined by the number of does pregnant divided by the number of goats inseminated multiplied by hundred and it is expressed in per cent. Out of 6 does inseminated one was found pregnant with 16.67% as conception rate in group I (Control). In group II out of 20 does inseminated 14 were found pregnant with 70.00% as conception rate (Table -4). Similar findings were reported by Riaz et al., (2011) [1] , Takle, (2018) [10] and Ahmad et al., (2012) with the conception of 60% by using ovsynch protocol. In contrast to this higher conception rate was observed by Thombre, (2016) [11] as 83.33%. The variation of conception rate with the present findings reported by earlier author could be due to difference in the breeds, drugs, physiological stage, seasonal variation, endocrine profile as well as geological difference which may causes variation in the conception rate. From the study it reveals that the group II was found more efficient than the control group of goats with 70% of conception.

Summary and Conclusion

Conclusion

 Estrous Induction protocol used with Artificial Insemination in Osmanabadi goats, group II showed 83.33% estrous response with less time taken for the onset of estrous as compared with the control group.  In group II goats by using GnRH, PGF2α and GnRH protocol, prolonged duration of estrous was observed  Conception rate was higher (70.00%) in group II which was found more efficient than the control group.

Conflict of Interest Not available

Financial Support

References

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